25-308 AI Load Data?

[Shu]

Does anyone have load data for the 25-308 AI? I've cautiosly worked up a few loads in my son's rifle, but would like to see what others have done for reference.
Also, what powders have you found to work best, particularly for the mid-heavy bullets 100 to 120 gr.?

 

[std7mag]

260 Rem data should get you close.

Be aware, the AI on the 308 family of cases doesn't give you the volume increase you possibly expect, based upon experience with 7mm-08AI.

 

[Shu]

So far I've used Vht N560, W760, H414, H4831SC and H4350EX. I'm trying to work up hunting loads for the 115 Nosler Partition.
It seemed to like the W760, but I would like a more temperature insensitive powder.
H4831SC was unimpressive.
H4350EX is showing potential. It looks like I can go a little higher than the 45 gr I shot today giving ~2920 fps.
I've been really impressed with Varget in my 250 Sav AI, but that powder seems a bit fast for this case, based on published 260 remington data.
I also have H4895EX on hand, but it seems to be in the same speed range as Varget.
Norma magnum rifle powder seems like it may work.
Any thoughts from those of you who've worked with the 25-308 AI? What's your favorite powder?

 

[Bill Norris]

260 Rem data should get you close.

Be aware, the AI on the 308 family of cases doesn't give you the volume increase you possibly expect, based upon experience with 7mm-08AI.

My builder (WSMNUT here on the site) told me when I was asking about the 260AI & 243I that the 7-08 and 308 would not realize enough gains to bother with them. However both the 243AI & 260AI certainly realize a rather large gain. I would expect the 25 cal. would also realize a fair amount of gains as well.

 

[358WCF]

I've been messing with a 257 Roberts Ackley a bit lately which is similar in case capacity to your 25-308. If you can lay hands on some Ramshot Hunter, it has worked very well in my rifle with 100s & 110s so far. Hunter is not touted as temp resistant, but hasn't shown any weirdness yet in other cartridges hot/cold. WLR primers light it off uniformly.

RL26 has been the velocity champ, as expected, but am trying to phase out RL powders. Some N560 is supposed to be on the way, but haven't used any yet. RL17 & RL23 were very good with 100s as was N160, N555, & IMR 7828SCC with 2nd place in velocity going to RL23.

Various 115s are in the queue, but haven't gotten to them yet beyond some initial tests with IMR4350 to get a feel for the rifle.

 

[ebb]

The 25 souper should be just what you are looking for. The description calls it a 25-308. A friend had one years ago and loved it. I just did a search and it popped right up so data is available.

 

[std7mag]

I've been messing with a 257 Roberts Ackley a bit lately which is similar in case capacity to your 25-308. If you can lay hands on some Ramshot Hunter, it has worked very well in my rifle with 100s & 110s so far. Hunter is not touted as temp resistant, but hasn't shown any weirdness yet in other cartridges hot/cold. WLR primers light it off uniformly.

RL26 has been the velocity champ, as expected, but am trying to phase out RL powders. Some N560 is supposed to be on the way, but haven't used any yet. RL17 & RL23 were very good with 100s as was N160, N555, & IMR 7828SCC with 2nd place in velocity going to RL23.

Various 115s are in the queue, but haven't gotten to them yet beyond some initial tests with IMR4350 to get a feel for the rifle.

The 257Roberts AI is going to have a significant increase in case capacity over the 25 Souper.
Also the Roberts is much lower in pressure than the Souper.

 

[358WCF]

The 257Roberts AI is going to have a significant increase in case capacity over the 25 Souper.
Also the Roberts is much lower in pressure than the Souper.

Please define "significant". You'll notice I stated similar in my previous post. Similar enough that 7-08 & 7x57 (the 257s parent case) start data (for modern rifles) & powders are virtually interchangeable. Start low & work up as prudent & possible. Lower pressure in the original Roberts is a whole 'nuther ball of wax, & not relevant here. With newly made brass in similar modern rifles I would have absolutely no qualms running either of the 2 at the same 60K+ pressures.

The fact that both cartridges being discussed above are Ackley Imps. makes your point even more moot. There is no data for 25 Souper or the Imp. version, while 257 Roberts with 85s hold 53.6gr of water, and the 257 Robts. Imp. holds 58.5gr. per Nosler #9. Just below a 10% increase. Maybe that's why near max loads for the standard Roberts make such good fireforming loads for the Improved version?

Using the parent cases & Nosler #9 as a guide, the 7x57 with 120s has 54.3gr water capacity, while 7-08 has 50.4gr. About 8% difference. I'm unsure how much of an improvent an Ackleyized '08 case gets. Likely less than the more tapered x57/Robts. case. These capacities are also dependent on seating depth &/or the make of brass used which could conceivably negate any capacity differences between the 2. That's certainly similar if you ask me.

Stepping up to the 280 Rem, we have 65.4gr capacity with 120s. Better than 20% increase over the 7x57 & over 28% larger than 7-08. Not really too similar.

I stand by my original statement that the 2 cartridges are of similar capacity, & the useful powders may very well be the same with the individual rifles peculiarities & component combinations being the deciding factor.

 

[Fast14riot]

Speer manual #4 has 25 Souper data.

 

[kyotekiller25]

The only Ackley really worth doing is the 280. Everything else is a moot point...

 

[Bill Norris]

When I see 200 + fps over the parent case I disagree.

 

[kyotekiller25]

200+??? Seems a little far fetched in my opinion.

Most AIs only give you 100-125fps gain. Where's the other 75-100+ coming from? My guess is pressure, or maybe an extra 4" of barrel. Otherwise 200+ is not realistic

 

[Fast14riot]

200+??? Seems a little far fetched in my opinion.

Most AIs only give you 100-125fps gain. Where's the other 75-100+ coming from? My guess is pressure.

260AI is quite impressive! 3000fps with a 140gr bullet at normal pressure limits is common. I can push 153.5's over 2900 with safe pressures, too.

 

[kyotekiller25]

Perhaps. Do you have a way of measuring that pressure?

3000 with a 140g from even the 260 AI with anything less than a 26" barrel is not going to be done with normal pressure limits. Maybe max pressure limits, a 26"+ barrel, a fast barrel, and the right powder.

It doesn't add up, unless you're running high pressure, which the AI hides fairly well because of the case design.

If AIs all did 200-250fps over the parent cartridge, than there would be no need for magnums. And everybody knows there is no replacement for displacement. And pressure is a direct correlation to velocity.

I mean why even have a 264 Win Mag at that point. It only does a comfortable 3000-3100 with a case full of Retumbo and 140s in a 26" barrel...Ask me how I know that. Sure I can ramp it up to 3250fps and say that's normal, but we both know that's a lie, and that's over pressure, plain and simple.

There's nothing magic about a 260 case or an AI.

 

[Bill Norris]

I get @ 3050 fps with the 140 gr. Berger L R Target and 44.8 gr. H-4350 in a 26 inch barrel with no pressure signs and been doing it well over 4 years shooting the same brass. Primer pockets remain tight so I see no need to change anything. My 243AI will get 3200 fps with the 115 gr. Tubb from a 26 inch barrel with no pressure signs using the same brass for over 4 years as well.

 

[Bill Norris]

200+??? Seems a little far fetched in my opinion.

Most AIs only give you 100-125fps gain. Where's the other 75-100+ coming from? My guess is pressure, or maybe an extra 4" of barrel. Otherwise 200+ is not realistic

If far fetched is your polite way of saying I'm lying come witness it for yourself. I have no reason to lie or nothing to hide.

 

[Fast14riot]

Not all AI chamberings are the same, some do gain much more than others. 243, 260 both being on the upper end of gains over parent case. There are a good number of us on here that shoot the 260AI and those numbers are very normal and not at max loads.

 

[Bill Norris]

Not all AI chamberings are the same, some do gain much more than others. 243, 260 both being on the upper end of gains over parent case. There are a good number of us on here that shoot the 260AI and those numbers are very normal and not at max loads.

Thank you Sir.

 

[358WCF]

The only Ackley really worth doing is the 280. Everything else is a moot point...

Not to start a pissing match, but what gun rag or website did you read that statement in? In modern bolt action & single shot rifles, 30-06, 257 Robts, the 30-30 family (including 219 Zipper & 25-35 Win.) all can gain a fairly sizeable amount of velocity due to not only the "improvement" of powder capacity, but also by running equal pressures to higher intensity rounds based on the same case... i.e. 270 Win (65K) vs 30-06 or 280 Rem (60K). The Robts. in +P mode is limited to 54K, 7x57 to 51K, the 30-30 to 42K no doubt in deference to the usual lever guns it's chambered in.

Another disturbing trend, short barreled Ackleys are an oxymoronic development in an attempt to offset the velocity loss from... wait for it... short barrels.

It was (take your pick) on the internet, on TV, in a magazine, in the AMA Journal, so it must be true. There are so many "established facts" (read: opinions) out there that just aren't true.

Color me skeptical. Rain's stopped. I'm taking 2 of my Ackleys & the chronograph to the range so I can flirt with disaster.

 

[Bill Norris]

Not to start a pissing match, but what gun rag or website did you read that statement in? In modern bolt action & single shot rifles, 30-06, 257 Robts, the 30-30 family (including 219 Zipper & 25-35 Win.) all can gain a fairly sizeable amount of velocity due to not only the "improvement" of powder capacity, but also by running equal pressures to higher intensity rounds based on the same case... i.e. 270 Win (65K) vs 30-06 or 280 Rem (60K). The Robts. in +P mode is limited to 54K, 7x57 to 51K, the 30-30 to 42K no doubt in deference to the usual lever guns it's chambered in.

Another disturbing trend, short barreled Ackleys are an oxymoronic development in an attempt to offset the velocity loss from... wait for it... short barrels.

It was (take your pick) on the internet, on TV, in a magazine, in the AMA Journal, so it must be true. There are so many "established facts" (read: opinions) out there that just aren't true.

Color me skeptical. Rain's stopped. I'm taking 2 of my Ackleys & the chronograph to the range so I can flirt with disaster.

Thank you Sir. Yea, these new keyboard warriors come on here and act like they know something but in reality it's easy to see they know nothing at all about a particular subject. Sometimes it would be in their best interest to keep quiet concerning certain interest until they learn the real facts. Next time maybe he should rub a little "fairy dust" on his keyboard for better luck. He absolutely struck out on this one. The 280 is definitely NOT the only cartridge out there that can and has benefited greatly from the AI status.